Drum type sewer cleaning machines of the type to which the present invention is directed are well known and are shown, for example, in U.S. Pat. Nos. 2,468,490 to DiJoseph; 2,730,740 to O'Brien; 3,007,186 to Olsson; 3,394,422 to Siegal; 3,095,592 to Hunt; 3,134,119 to Criscuolo; 3,246,354 to Cooney, et al.; 4,364,139 to Babb, et al.; 4,580,306 to Irwin; 5,031,276 to Babb, et al.; and, 6,009,588 to Rutkowski. As will be seen from these patents, it is known to provide a drum type sewer cleaning machine comprising a frame structure supporting a rotatable drum and a drive motor arrangement for rotating the drum and a cable stored within the drum, and to provide for the drum to be removable from the frame and drive arrangement to, for example, facilitate replacement of the drum with one containing a cable having a different diameter. It will also be seen from these prior art patents that such drum type sewer cleaning machines may include a cable feeding arrangement supported by the frame and by which the cable is adapted to be axially displaced relative to the drum during use of the machine. In these feeding devices, typically, a set of stationary roller wheels are moved into selective engagement with the rotating cable. The wheels are held at an angle relative to the rotational axis of the cable to thereby axially urge the cable out from and into the rotating carrier member where it is stored.
Simple devices for monitoring the length of cable material payed out from a sewer or drain cleaning machine are also known in the art, such as noted in U.S. Pat. Nos. 3,394,422 to Siegal; 4,546,519 to Pembroke; 4,540,017 to Prange; and 5,009,242 to Prange. These patents are generally concerned with measuring the length of a cable displaced into a drain being cleaned. However, in these patents, the cable material in the sewer cleaning device is not rotated about its axis, and is not in the form of a helically wound member. In addition, in several of these patents, the cable counting device requires a direct physical contact with the drain cleaning cable which could in some circumstances cause the counting device to become contaminated by debris carried by the drain cleaning cable. Thus, these devices are somewhat limited and, further, do not encounter the same problems as are encountered in connection with monitoring the displacement of such a rotating cable coiled inside a rotating drum.
Accordingly, there is a need for an electronic cable monitoring system configured to assess an amount of drain cleaning cable payed out from, or retracted into, a rotating drum of an associated drain cleaning apparatus without the need to directly contact the cable and while permitting drum rotation. There is a further need for a drain cleaning apparatus including a frame, a drum, a flexible drain cleaning cable, and an electronic cable monitoring system configured to assess the amount of cable payed out from or retracted into the rotating drum of the apparatus.
There is an additional need for an electronic cable monitoring system configured to determine an amount of drain cleaning cable payed out from or retracted into a rotating drum of an associated drain cleaning apparatus on a per job basis as well as on an overall or historical basis. There is a further need for a drain cleaning apparatus including a frame, a drum, a flexible drain cleaning cable, and an electronic cable monitoring system configured to determine the amount of cable payed out from or retracted into the rotating drum of the apparatus on a per job basis as well as on an overall or historical basis. Additionally, a need exists for a method of determining and notifying, such as via a visual indicator such as a light or notification on a visual display, or by an audible indicator such as a speaker, of cable payed out or retracted. The use of such indicators would provide a convenient way for informing an operator as to cable pay out or other operating conditions.
There is yet a further need for an electronic cable monitoring system configured to measure a time of use of the machine on a per job basis as well as on an overall or historical basis. There is a further need for a drain cleaning apparatus including a frame, a drum, a flexible drain cleaning cable, and an electronic cable monitoring system configured to measure the time of use of the machine on a per job basis as well as on an overall or historical basis.
A condition that may occur when using a powered rotary drum drain cleaning device is “cable loading.” This condition can occur when a rotating drain cleaning cable encounters blockage or other obstruction(s) which can suddenly restrict rotation at a distal end of the cable. The machine-end of the cable however, is still undergoing rotation, and so the cable becomes wound or twisted about its longitudinal axis.
Various techniques have been used to assess a cable loading condition such as excessive current draw of the motor. For example, U.S. Pat. No. 5,199,129 describes a sensor for measuring motor drive torque. A sensing circuit is also described that activates one or more notification lights when the motor drive torque exceeds a selected allowable torque level. These techniques are based upon a cable loading situation as it is occurring. Other strategies do not attempt to detect such conditions and instead, use clutches or similar devices to divert application of rotary power from an already over-stressed cable.
Although satisfactory, a need remains for a method of predicting a cable loading condition during operation of a powered rotary drum drain cleaning device.
It would also be desirable to detect other conditions that may occur during operation of a drain cleaning device, such as reverse rotation of a drain cleaning cable, and in particular, prolonged existence of this condition. Extended use of a cable undergoing reverse rotation can result in permanent damage to the cable.